Grinding machine



m vn LE, ame. HCE. cm@ nGd Mmm amp .wn R .m g .l r o Dec. 4, 1928 R. c.MITCHELL GRINDING MACHINE Original Filed Aug. 8.A 1921 8 Sheets-Sheet 2ImfnT l Dec. 4, 1928.

R. C. MITCHELL GRINDING MACHINE Original Filed Aug. 8, 1921 8Sheets-Sheet 5 Ng wd i 8 Sheets-Sheet 4 Dec. 4, 1928.

R. C. MITCHELL -c-MNDING MACHINE Original Filed Aug. 1921 Dec. 4, 1928.1,693,723 R. C. MITCHELL Y GRINDING MACHINE original'med Aug. a. 1921 ssheets-sheet 5 [mieli-131;

Dec. 4, 192s.

R. C. MITCHELL GRINDING MACHINE Original Filed Aug. 8. 1921 8Sheets-Sheet 6 rm @um Mam/M Dec. 4, 1928.

R. C. MITCHELL GRI NDI NG MACHINE Original Filed Aug. 8. 1921 8Sheets-Sheet 7 8 Sheds-Sheet 8 Dec. 4, 1928.

R. c. MITCHELL v GRINDING MACHINE original Filed A'gQs. 1921 Patentedlec. 4, 1928.

UNITED STATESl PATENT oFFICE. y

RAYMOND C. MITCHELL, OF SPRINGFIELD, OHIO, ASSIGNOR, BY MESNE ASSIGN-MENTS, TO BARBER-COLMAN COMPANY, A. CORPORATION OF ILLINOIS.

GRINDING MACHINE.

applicati@ filed August a, 1921, seriai My invention -has Afor itsgeneral object to improve grinding machines--and in some of its featuresmorev particular'l grinders of the sort shown in my prior atent No.1,335,905, and my pending application Serial No. 403,999, filed August16, l920-in matters affecting flexibility of operation; concerningranges of speed of the work-rotating and table-traversin operations andcross-feeding without ta le reciprocation; accuracy' of setting fortaper grinding; smoothness of operation and avoidance of shock and jars;eiiciency and convenience of' manual control; and economy and generalimprovement in mechanical construction making for minimum expense inmanufacture. Y

Other and further objects of my invention will become apparent from thefollowing description, taken in conjunction with the aecompanyingdrawings, wherein I have shown a preferred form of grinder embodying myinvention. a

In the drawings, which in some respects are diagrammatic, departing fromshopdrawing proportions whereV exaggeration seemed to clarify theconstruction, Fig. l is a .front elevation of a grinder embodying myinvention; Fig. 2 is a side elevation thereof;

Fig. 3 is a plan detail viewed from line,

3-3 of Fig. 2; Fig. 4 is a detail in elevation viewed from line 4-4 ofFig. 2;.Fig, 5 Ais a front elevation with parts broken away tol showgearing and gear housing; Fig.- 6 is a section on line 6 6 of Fi 5;'Fig.7'is a detailed'section on line 7 of Fig. 1; Fig. S is a plan detail ofa portion of the tabledriving gearing, Fig. 9 is a schematicallyextended View 1n plan of portions of the table-driving and work-rotatinggearings; Fig. 10 is a detailed section on line 10-10 of Fig. G; Fig. 11is a detailof the hit-or-miss con-l trol devices on the front plate;Fig. 12 is an enlarged detail, With'parts broken away, of some of thecontrol devices, viewed from'thc front of-the machine; Fig. 13 is asection on line 13-13 of Fig. 12; Fig. 14 is a front elevation withparts broken away of a modilied table-check and'Fig. 15 is a section online 15-15 of Fig. 14.

0n t-he'main frame 20 the slide table 21 is mounted vfor longitudinalreciprocation drive 32 an 210.490.479. ,Renewed october 1, V

and upon the table the swing plate 22 is centrally pivoted in knownVfashion, head-stock 23 and foot-stock 24 being mounted on said. swingplate for longitudinal adjustment thereon in .known manner.` Grindingwheel. 25 Vis mounted in the carrier 26, capable of transverse orcross-eedingmotion at right angles to the line of table travel, andconstructed and mounted for the usual adjustments.

I preferably provide for rtating the grinding wheel,^driving the workand reciprocating the table from the common power shaft 27, which itselfmay be driven in any suitable fashion as by a pulley rigging 28,

such shaft being preferably carried in brackets mounted on. the exteriorof the frame casting 20. It may drive the grinding wheel spindle bybelt`29 running over pulleys on the respective shafts and suitableidlers on the belt-trunk 30 that, to accommodate mo'vements of wheelcarrier 26, is pivoted on the power shaft 27 and has adjustablelink-connection at 31 to-the wheel carrier. The power shaft 27 ma beconnected by a silent chain dy suitable sprockets with the jack; shaft33, which-acts as a driver from which motion may be imparted to both thetablereciprocating mechanism' and tlie workdriving mechanism. Shaft 33and as much as is possible of the gearing and shaftingl associatedtherewith, and the control devices, are all mounted in a sub-frame 34that is structurally independent of main frame 20, so that assembly ofmost of the parts as to whichnice fitting is necessary, may be made Y.without providing shaft bearings in the Amain frame. The sub-frame 34is preferably integral with the front plate 34 whichoovers a largeorifice in the front of the main frame and is readily demount-able withall its mechanism. Preferably the sub-frame is made as a gear box closedat ends and sides to form a convenientpil'well.

As is schematically shown in Figs. 8 and 9, jack shaft 33 has its pinion35 arranged to drive gear 36 on what I may term the main shaft 37 of thegear-nestfrom which power may be transmitted through one set ofspeedchanging gearing 38 to drive the table reciprocating mechanism andalso, through another speed-changing transmission 39 to drive one of theis shifted longitudinally within the shaft.

the work-rotating mechanism (which, as in On reverse-gear shaft 54, thatis supported my co-pending application No. 403,999, is wholly geardriven).

Table driving mechanism.

, shown provides a hollow shaft 41 paralleling 'l L `the main shaft 37'andhas loosely mounted upon itthe four gears 42.0f different sizesconstantly meshing with the inversely vary- .ing gears/43 on the` mainshaft. A rod 44 slides in the hollowY shaft, carrying a -yielding key 45as shown in Fig. 10, that is springpressed laterally to protrude itsblade` through a slot 46 in a hollow shaft, so that it may clutch intothe suitable hub-slot of any gears 42, accordingly. as the rod Forspeed-changing control shaft 47 runs through the face plate 34"andcarries handle 48 "co-acting with index dial 49, such ad \\`\44.Preferably spacing rings 52 between shaft aving thereon a gear 50 (Fig.10) meshing with a cylindrical rack 51 on rod gears 42 present bevelededges to co-act with the beveled ends of plate\45 to insure passage ofclutch plate from engagement with one gear 42 with another with a snapaction. Said rings serve to prevent the possibility of; two beingclutched to shaft 41 at the same time.

Thus, from constantly running shaft 37 shaft .,41 will be runpractlcally constantly at #any one of., four selected speeds.'

Table reversing gearing is provided in conjunction with the change-speedgearing` preferably-:interposed between the four speed transmission andthe high-and-low speed gearing. Reversing gear shaft( 54 (Figs. 8 and 9)parallels shaft 41 and is constantly driven therefrom, but in theeffective geartrain I preferably provide a shock-absorbing or yieldingconnection for taking up strains that otherwise might be caused bychanging the gear ratio in'thev four-speed transmission while themachine is running. 55

is a gear on shaft 41, constantly driven there,- bv and meshing withgear 56 on shaft 54. Gear 55, however, preferably has yieldingconnection with shaft 41. Fixed on shaft 41 is a three-armed spider 57,(Figs. 6 and 10), between the arms of which spoke-lugs 58 of gear 55extend, springs 59 being interposed between the spider arms and spokelugs, to give the tooth rim of the gear the capability to yield in adirection opposed to the driving rotation of the gear, fer` shockabsorption purposes. In short, thejspider drives the rim through thespring.

that extends through front plate 34 and carries the manual and automaticlever means i Vfor effecting reversals of the direction of tabletraveled. A suitable flop-over device 65 of known construction insuresthat the clutch sleeveI will always stand in one or the other of itscluif-hing positions.

Gears oJ-60 constantly mesh with gear 66 on a cross-shaft 67.from whicha'rackgear 68 may be driven throughv either the i high-speed orlow-speed train, or allowed to idc. according tothe positionof thehandle 69 on the front plate 34. As diagrammatically7 shown in 8,shaft67 has loosely mounted thereon gear 70 that is in a reducing trainleading to pinion 71 that meshes withy rack-gear 68,v and also carries aloosepinion 72 that is in an accelerating train leading to the pinion71, these gear-elements 70'and 72 having confronting clutch members 7 3for coaction with a clutch member 74 non-rotatably mounted on shaft 67and slidable thereon from ancutral central'positio-n into positiveclutch engagement with either of the gearelements 70 and 72. lA shifterlever -75 controllin to be cammed axially by a pin and slot arrangement77, the slotted Sleeve of which is carried by control handle69.

One of the gears of the train driving rackgear 68 may mesh with pinion78 directly on the shaft of a hand wheel 79 mounted on the front plate34 for enabling'the table to be moved by hand power. The rackear 68, itwill he understood, meshes direct y with a rack 86 carried by the tableas shown in Fig. 5.

It will now lbe apparent that according to the selective positioningofcontrol handle 69, table travel will be in the higher range. of Speedor the lower rangenof speed, or the table may be caused to remainstationary by throwing said handle into middle, neutral pofr clutch 74is mounted on a slide rod 76 lll) sition; and in whichever range 0fspeed-,the l s machine ma be 'caused to function table travel may e atany one of four selective speeds within that range accordingly" with the'selective position of handle 48.

` Work rotating mechanism.

In my prior application, Serial No.403,999,

gear mechanism for impartingv rotation to the driving element 23 of thehead-stock is bearings fixed in said table and said shaft 81A This shaft81 being slidable through pinion upon reciprocation of the table.Connection is effected between shaft 81 and driving element 23 through agearing in the swiveled housing 82 to drive a shaft 83 that may slidelongitudinally through said housing-contained gearing, and that isequipped with a flexible joint -84 acting, in connection with theswivelling operation of the housing, to accommodate lateral displacementof the swing-table. In any position of the head-stock as to axialadjustment on theswing-plate, and lateral adjustment caused' by movementof the swingplate the drive from shaft 81 is effective.

is of square or other non-circular section and slides through arotatable pinion 85 which is held against longitudinal movement by itsmounting in the bracket 86 (Fig. 5) cast in or otherwise secured to thesub-frame. 84. This pinion may also be driven in high or low speedranges, and with a speed-variation in either range, as diagrammaticallyshown in Fig. 9. To this end the change-speed transmission 39 has gears42 and control mechanism worked from handle 48 identical in substancewith the changespeed transmission described heretofore, the yieldinglymounted gear 55 thereof having a broad toothed surface making constantengagement with a gear 87 that has clutch-hub members-on both sides andthat is slidable axially on shaft 88. In central position this gearturns the shaft 88 idly. At opposite ends of its sliding throw itsclutch members engage clutch elements of gears 89, 89', loose on shaft88 and respectively meshing with small and large gears 90-90 fixed onshaft 91, one of said gears meshing with the pinion 85, so that saidpinion is driven in its high speed range when gear 87 is shifted to theleft (Fig. 9) and low speed range when the gear'87 is shifted to theright. Shifter' arm 92 engages the sliding gear 87 and the slide rod 93for said arm is worked from control handle 94 on the front plate, theshort shaft 95 (Fig. 5) for said arm having a finger 96 engagin betweencollars 97 on said rod 93.

It wil now be apparent that by handle 94 the gearing for work-rotationmay be thrown from neutral, inert condition into low-speed or high-speedratio, and by operation of handle 48', any one of four selective speedswithinthe general range may be employed.

A11/tornati@ tablen--Reoz'procation and mtomatw cross-feeding.

In general the mechanism for automatically reversing the direction oftable travel and for automatically effecting a cross-feed of thegrinding wheel stand 26 are similar to those shown in my prior PatentNo. 1585.905. Adjustable lugs 101 on the table may strike arm 102 Fig.6) of a lever fast on the rock-shaft 64 which controls the tablereversing clutch 62. A hand lever 103 provides for manual control inknown fashion. An arm 104 of lever 102 (Figs. 11 and 12) co-acts withshiftable frame 105 carried on the cross-feed lerer 106 to depress thelatter at each swing of arm 104 (when frame 105 is suitably positioned),cross-feed lever 106 operating through suitable ratchet' and pawlmechanism 107 (as more fully set forth in my said patent) to rotate,step by step, the cross-feed shaft 108. This shaft (Fig. 6) makes wormand worm wheel connection 109 with the vertical shaft 110 on which thewheel stand 26 centers, and the pinion 111 of such shaft meshes withrack 112 of the sliding head of said wheel stand.

It is very desirable, at times, to operate the cross-feed automaticallywhen the table is not reciprocated, and of course under suchcircumstances cross-feed lever 106 will not be actuated by arm 104. Iprovide for the condition stated by arranging to drive the ratchet andpawl mechanism from a constantly rotated part of the gearing, at will,preferably by connections associated with the cross-feed lever 106 andso arranged that actuation of' said cross-feed lever from theconlstantly rotating part or from arm 104 are alternative, and cannotpossibly be concurrent. For this purpose I bring the constantly rotatingcross-shaft 67 of the reversing gear mechanism through the face-plate ofthe ma- -chine and equip it (Figs. 11 and 12) with an eccentric or cam113 (although of course any constantly operated part, suitablypositioned, might be utilized in lieu of shaft 67). The slide frame 105I make adjustable along the lever 106 as by rock and pinion connection105 to a point that takes it out of the range of motion of lever 104,and this frame I equip with a stud or block 114 that', with the frame atsaid extreme of movement, may serve to elevate into the path ofoperation of cam 113, a striker member 115 that takes the form of a barpivoted co-axially with lever 106. As long as frame 105 is in any sitionwhere it can be operated on by arm 104, block 114 is moved to the leftof the position shown in Fig. 11 allowing the nose of striker member 115to drop behind it, so removing the striker member from the field ofoperation of the cam 113. However, with the parts positioned as shown inFig. 1`1, each rotation of shaft 67 will cause a depression of lever106, and consequently a cross-feeding operation.

Cfr

To insure proper oilingy of the mechanism I provide an oil pump 117(Fig. 6), mounted in proximity to the oil VWell of the gear casing, andpreferably on the front plate 34. The spring pressed piston 118 ispreferably worked by an eccentric 119 on a constantly running shaft ofthe gearing, and a piping connection 120 to the valved' intake side ofthe, pump chamber shown leads through a glass-fronted gauge chamber 121i and to the lower p art of the oil'well. The

` front of the machine, the contracting adjustment of bolts 128 for thesplit cylinder caus ing it to grip with desired frictional resistancethe solid roel 129. Striker blocks 130 mounted adjtistably on thesliding table (preferably in tandem with the lugs 101),

'may strike the rod 129 in suitably timed relation to the operation oflugs 101 on the table reversing mechanism, so that a portion of themomentum of thetable is taken up by the friction cliecledevice, andshocks to the ef'l'ective mechanism are greatly reduced and smoothnessof operation most effectively enhanced. In Figs. Hand I have shown amodified construction in which spring pressed plungers 129', held inprotruded position in respect to solid cylinder 1,27 by the action ofsprings.131, are employed, either spring resistance or frictionalresistance being effective in'the checking operation.

In angular, or taper grinding, yit is often important to make veryminute changes, laterally, in the positionlot the swing-plate, and Iprovide means for facilitating the obtaining of greatest nicety inmaking such adjustments, or securing for a second operation theidentical position that was hadfor the first. As shown in Figs. 3 and 4,the end of lthe swing-tatie usually has a graduated scale 132 for aid indetermining its adjustment, but

micrometric accuracy is difiicult to attain. I provide, therefore, onthe slide-table and the swing-plate respectively, a micrometer andanadjustable stop soV related that the micrometer may be brought intooperation at any point in the swing of the table, according to thesetting of the movable stop, and

adjustments fromithat point determined With the greatest accuracy.Specifically 133 represents a frame'rigid on the slide table and havinga cross-bar 134 along which a stop member 135 may be slid and secured inany adjusted position by screw 136. c The arm 135 of this stop-deviceprojects into the path of the actuating stein 138 of a suitable rotarymicrometer 139. The swing table may be roughly set to approximateposition desired and then the stop-device 135 adjusted to press uponmicrometer actuating it to show any selected reading. From this settingthe operator can Work both ways with greatest nicety, and of course bynoting the .micrometer reading at time of finishing one piece of Work, aduplicate can be reproduced. With greatest accuracy by maintaining thesetting of the stop and Working until the micrometer reading isduplicated.

While I have herein described in detail a particular embodiment of myinvention that is desirable in many details that I may claim forspecific benefits, it will be understood that in the broader' aspectsot' my invention many changes and departures may be made from thespecific construction shown Within the spirit of my invention and thescope of the appending claims.

I claim:

1. In a grinder. the combination of a slide table, a grinding-u'heelstand, cross-feed mechanism for the latter. automatic means forreciprocating the table, said table reciprocating means having operativeconnections to actuate the cross-feed mechanism. a constantly-movingpart and means operatable from said constantly-moving part for actuatingsaid cross-feed independently of table reciprocation.

2. ln a grinder, the combination of a slide-table, agrinding-Wheelstand, cross-feed mechanism for the latter, having ashiftable part. automatic means for reciprocating the table. said tablereciprocating means having operative connections to actuate thecrossfeed mechanism, a constantly-moving part and means operatahle fromsaid constantly moving part for actuating said cross-feed independentlyof table-reciprocation, said shiftable parts being movable to renderidle either operating mechanism alternativelv.

3. In a grinder, a slide-table, a swing-plate 'pivoted thereon, and ashiftable stop and a micrometer-gauge operatable by coaction With saidstop, one associated With the table, ythe other with the plate.

4. In a grinder. the combination of a constantly-running shaft. areciprocable slide table arranged to be reciprocated or stopped at will,a grinding wheel stand, crossfecd mechanism for thelatter including avibratahle member (106) and dual means for actuating said membercomprising an operating part moved hv the slide table. an operating partmoved by the constantly running shaft and shiftable means forestablishing operative connection between said member and either of saidparts at will.

5. Structure as set forth in claim Aft. wherein the vibratahle armcarries tu'o elements for respective coaction with the tivo operatingparts and one of these elements is arranged, but only When removed fromcoactive relation to its actua" ig part. te hold the other elc ment incoactive relation to the other actuating part.

6. Structure as set forth in claim 5, Wherein the respective operatingparts are a lever (104) and a cam (113) and the tWo elements are a slidemember (105) on the vibratable arm (106) and a striker member (115) foreoaetion with the cam, said slide member being arranged, vvhen moved ontof the path ot said lever (104) to latch the striker member in the pathot' the cani.

7. In a grinder, a slide-table, a swing plate pivoted thereon, a frameon the table having a stop thereon adjustable transversely of the table,and a micrometer gauge carried by the table having an actuating stem sodisposed as to strike said stop when the table is swung.

8. In a grinder,- the combination With a frame, a driving shaft and apart to be driven; ot a tirst variable-speed selective transmission. amotion reverser anda second variable-speed selective transmission,connected together in series in said sequence, said first variable speedtransmission being adapted to effect a continuons driving relation atone of a plurality of speeds and said second variable speed transmissionbeing adapted to etl'eet a driving relation at either ot' two speeds orto interrupt the driving relation entirely.

i). In a grinder, the combination with a trame, a driving shaft and apart t0 be driven, ot' a gear train connecting said shaft and said partincluding, in tandem driving relation, two Variable-speed selectivetransmission gear mech anisms` one of said variable speed transu'iissionmechanisms being adapted to eifel-t a continuons driving relation at anyone of a plurality ot' speeds and the other variable speed transmissionmechanism being adapted to effect a driving relation at either ot' t\vospeeds or to interrupt the driving relation entirely.

In testimony whereof I have hereunto subscribed m v naine this 12th dayof July. 1921.

RAYMOND C. MITCHELL.

